Zane Gifford surveyed the loading dock at the base of a 20-story office tower in the Galleria area and recalled the Memorial Day flood of 2015.

Nine feet of water inundated the basement of 3000 Post Oak, flooding mechanical equipment, the management office and the employee deli. It took Gifford, the building's chief engineer, a week to reopen the tower, a month to get it off the standby generator and nine months to fully restore everything.

"These dumpsters were floating around," Gifford said, pointing inside the loading dock. "You don't want to go through what we've been through. It's stressful."